add output to stream of lines (seq string) ?

[jkone27]

would be useful to process the output as stream, like less or more commands, so as a stream of lines, and to have control to interrupt or modify the behaviour of code based on content

e.g.

dotnet test |> break if containing 'Exception' so it will stop at the first error in tests instead of running the full suite

[CaptnCodr]

Hey @jkone27, thank you for raising an issue.
That's a good idea. I'll tackle this soon-ish.

[jkone27]

yes i think this could be useful to chain the printing of executing command while a command is still running or is not exiting,
maybe also in this contrext would be useful to add a way to chain a command only when the previous one was "killed" with CTRL+C, so that instead of exiting the program, it will bring back the execution to the next step first

cli { ... some long running process printing } 
|> some cleanup tasks to run anyways even if the above program is stopped

one example case is when running python scripts you might want to exit the virtualenvironment always at the end, so i need to run a "closing" python command even if the running program is interrupted... but this is a very special case i guess.

[CaptnCodr]

Is this the wrong issue for your comment? 😄

[CaptnCodr]

Anyways, I think that is a special case, yes.
My first thought is to await for this process and look at the exitCode of the process and run special things for cleanup.

[CaptnCodr]

Thoughts on this:
Output.Stream of standardOutput: Stream * standardError: Stream
Filling standardOutput from Process.StandardOutput (stdout) & standardError from Process.StandardError (stderr)

[johnW-ret]

Bump.

This is a great wrapper but there's a bigger issue other than just having eager access to shell output. Upon inspection of source, it appears that output text is always captured in memory - even when writing to a file. It appears that the only cases where Option.Text can be None is when shell output is empty (?).

This breaks all use cases where a script prints out more text than there is memory available, and the library will capture output as memory even if it is not used by the consuming program.

A good start would be to rewrite the File option to simply forward writes to a file realtime and flush at the end but I'm not sure how changes could be made without introducting breaking changes as changing Output.Text to None in this case would technically not be correct. This, of course, would not fix the issue where output is stored in memory even when not used.

[CaptnCodr]

@johnW-ret Does PR #80 meet those requirements you mentioned?